This invention is related to a mold assembly for injection-molding flat-type heat sinks.
It has been found that electronic devices such as power supplies are usually sealed within a casing thereby causing problems in cooling the electronic devices. Hence, it is proposed to provide a metal heat sink within the casing.
Most of such heat sinks are generally U-shaped in cross section and partly covered with plastic. As shown in FIG. 1, the metal heat sink 12 is disposed between the male mold 10 and the female mold 11 between which there is a clearance (a) which will cause difficulties in engaging the male mold 10 and the female mold 11 thereby easily causing damage to the molds. Hence, it has been proposed to engage the male mold 10 with the female mold 11 closely without the clearance (a). However, there will be a negative clearance (b) and the plastic will be excessively squeezed to cover the portion (c) which is designed to be not covered by plastic, thereby making it unfit for practical use.
Therefore, it is an object of the present invention to provide a mold assembly for injection-molding flat-type heat sinks which can accurately injection-mold a covering for a flat-type heat sink without causing damage to the mold assembly.